Does it make sense to swich note and mode depending on the chord being played?

Question

So, C Aeolian and A# Mixolydian have the same notes right? That means that the difference is just which notes I emphasize, correct? Like, focusing on A# notes instead of C just makes the sound more ‘Mixolydian’ but still correct in C, right?

So my question is: let’s say I’m soloing over C Ionian. The chord progression is I-V-vi-IV (C-G-Am-F). Does it make sense to play over the chords like this:

• C: C Ionian
• G: G Mixolydian
• Am: A Aeolian
• F: F Lydian

Like, I could just play C Ionian over the entire chord progression, but it would probably sound better to emphasize the chords being played by switching modes and emphasizing the current chord being played by targeting that new root note.

Now, if the above is true, then I’m also trying to understand if it makes sense to play G Ionian (over the G chord) and F Ionian (over the F chord). If so, why would I do this? When is this used?

Does this make sense? Am I missing something?

Similar questions:

• Playing scales over I IV V progression
• How do you modulate between modes?

Answer 1

Preliminary

• C aeolian and A# mixolydian do not have the same notes. However, C aeolian and Bb mixolydian do. Even though A# and Bb mixolydian are enharmonically equivalent, the spelling is important.

• It's reasonable to say that the main difference between C aeolian and Bb mixolydian is the "home" note — the emphasized note. There are other differences, but for the purposes of this question, the difference in tonic note is sufficient.

Modes over I-V-vi-IV

Given only the main key (C ionian in this case) and the chord changes, yes, it's perfectly reasonably to play

• Ionian with I
• Mixolydian with V
• Aeolian with vi
• Lydian with IV

Further, one could indeed play C ionian over the entire progression, but, for example, emphasizing C against a G chord can give an unpleasant sound.

Matching mode to chord quality

This is a common approach to teaching jazz improvisation: pairing chord types with modes. Thus

• Major chord = ionian
• Minor chord = aeolian
• Dominant seventh chord = mixolydian
• Minor seventh chord = dorian
• and so on.

Where this has the potential to cause problems is when the larger harmonic context doesn't work for the scale chosen.

As an example, a piece of music in C ionian, and one reaches the IV chord (F major). The chord-scale approach would suggest F ionian. However, F ionian includes Bb, which could create problems depending on the accompaniment. An accompaniment that remains grounded in C ionian might through in B, which would clash with the Bb. In addition, hearing the Bb would suggest a key change (to F ionian), which may not be what the soloist intends.

General "rule"

When choosing a scale/mode to play with a particular chord, the main importance is the chord tones themselves. One can overlay any scale/mode that includes those pitches, and it can "work" as long as that scale fits the larger context — or as long as any accompanying instruments pick up on the scale being used.

Answer 2

There's little difference between C Aeolian and B♭ (not A♯) Mixolydian. They use the exact same set of notes, from the parent E♭ key. I guess you call it A♯ as a guitar player?

So saying 'should I use x or y or z' is a minor issue. Using the same notes over all the chords will inevitably work. It's targeting the better notes for each chord that's more of a question. And that involves more to the point in where those better notes are played. It would make some sense to play the root of the appropriate mode on beat 1 where that mode is prevalent, if that's what you're trying to do.

So, for me, thinking in seven different modes for the same solo in one key is somewhat unproductive, from that angle. Particularly as it's quite feasible to play any of the twelve notes available at any point in a solo. Sometimes we want one of those notes to sound 'off', then to sweeten the phrase with a 'good' note.

The concept of using Ionian for every major chord - e.g. bar of F - use F Ionian, bar of G - use G Ionian, isn't a particularly good one, as that heralds some sort of modulation, which in reality isn't going to occur. Having said that, sometimes it's nice to play games with the listener, and do just that, and give them a surprise!

And if one were to follow that through, which minor mode would one use for a bar with a minor chord? For that matter, which major mode should one use for the major bars? Often, soloing, one may use Mixolydian rather than Ionian anyway.

Summing up - as I've said to most students - all 12 notes are up for grabs, just about anywhere. There's a sort of ground rule that diatonic works (as a start point) but not actually in Blues, for instance, but using one's ear rather than a set of 'rules' is a much better bet, and generally speaking, will produce better solos.